A mobile crane crashed on to the street in front pedestrians and traffic in central Dunedin this morning.

No one was injured when the crane, operated by Dunedin Crane Hire and capable of lifting up to 70 tonnes, collapsed after completing installation of a cooling tower on the top of Dunedin Hospital about 10.45am.

The arm of the crane fell down Fredrick St and crossed the intersection with Cumberland St, where cars were waiting at the lights, the Otago Daily Times reported.

The crane driver, who was said to be very experienced, was shaken but unhurt by the incident.

Frederick St has reopened to traffic.